Testing an Abnormal Grain Growth Theory via Large-scale Phase-field simulations

Abstract

The mean-field theory proposed by Humphreys is frequently used to predict abnormal grain growth caused by nonuniform grain boundary properties. This theory enables the abnormal growth conditions of a particular grain to be described using only three parameters: the size ratio, grain boundary energy ratio, and mobility ratio between the particular grain and its surrounding matrix grains. However, detailed validation of the theory has yet to be reported. In this study, we elucidate the validity of the mean-field theory by performing very large-scale phase-field simulations of 2D and 3D abnormal grain growth based on parallel GPU computing. Systematic simulations are carried out while varying the initial size ratio, boundary energy ratio, and mobility ratio of a particular grain and matrix grains. Comparisons of the simulated theoretical results demonstrate that the abnormal growth behaviors (i.e., whether the abnormal growth occurs and the limiting size that can be reached by an abnormally growing grain) is well described by the mean-field theory.